The present invention is directed towards electron beam matrix deflection systems and, more particularly, to a novel electron beam matrix deflector formed by photoetching techniques and having a diverging aperture for preventing impingement of the deflected electron beam against the matrix member structure.
In many electron beam systems, a matrix lens, such as described and claimed in U.S. Pat. No. 3,534,219, assigned to the assignee of the present invention and incorporated herein by reference, is utilized to focus and then accurately deflect an electron beam to precise position on a target positioned parallel to the plane of the matrix lens and on the opposite side thereof from an electron beam source. Typically, the matrix deflector consists of a square array of apertures or slots (such as an 18.times.18 array having 60 milli-inch spacing between centers of adjacent apertures) wherein the deflection matrix is formed by a pair of members each having a plurality of substantially parallel conductors, having the aforementioned center-to-center spacing, with the slotted apertures of each member being aligned essentially orthogonal to each other and to the direction of incidence of the electron beam. Typically, each aperture in each member has a depth of about 150 milli-inches to provide the required deflection for an electron beam realizing a spot size, upon impingment on a surface of the target, on the order of 2 microns. Such matrix deflector members are generally realized by machining a set of slots in a ceramic member to leave a complementary set of bars which are subsequently metallized to produce the conducting electrodes necessary for producing beam deflection fields within the slots. The machining of slots in a fired ceramic member is a difficult and costly process, particularly when high slot tolerances and relatively great depth of cut are required. Accordingly, a method for making an electron beam matrix deflector at a relatively low cost and in highly accurate manner (and the lenses made thereby) is highly desirable.